Buying guide for best roof and gutter heat cables
Harsh winter conditions can be tough on people and pets. From dangerously icy sidewalks to salted roads when driving in snow, winter is a common time for injuries and damage to vehicles.
Winter weather is tough on your home, too. One of the most dangerous situations is one that you can’t easily see: an ice dam. An ice dam may form on your roof when temperatures bounce back and forth from above freezing to below freezing.
As the ice dam forms, it may be hidden under a pile of snow, so you cannot see the damage it’s causing. Fortunately, you can reduce some of the issues associated with ice dams by using heat cables on roofs and gutters. The heat cable prevents ice from forming, allowing the melting snow and ice to find a runoff path into the downspout and away from your home.
If you live in an area with snow and ice in the wintertime, investing in a heat cable now can save you costly repairs in the future. We can help you find a heat cable that meets the needs of your home.
Key considerations
Cable length
The primary consideration with heat cables is the length of the cable. These cables are not meant to be cut to size, so you want to purchase the length that’s closest to what you need.
Heat cables can be as short as three feet and as long as 250 feet. Purchase as much cable as you calculate you need — don’t try to save money by buying a shorter cable and hoping it does the trick. Without proper installation, the cable does not melt ice and snow properly. You cannot perform a proper installation with a cable that’s too short for the job.
When calculating how much cable length you need, pay attention to the length of the portion of cable with the heating element inside it. Deicing cables often have a section called a cold lead that attaches to the heated portion of the cable. The cold lead is the section you plug into an outlet; it doesn’t have any heating element. The cold lead may be as short as a few inches or as long as 10 feet.
Features
Automatic sensors
A heat cable for gutters may have a series of sensors built into it. These measure the temperature and moisture in the area.
With these sensors in place, the heat cable turns itself off and on as needed. This saves money, as it only draws power when there’s the potential of ice in the area. With automatic sensors, you can leave the cable plugged in all the time and forget about it.
Less expensive cables do not have automatic on/off switch sensors. Instead, you plug in the cable when you want it to operate and unplug it when you want to stop passing heat through it. These work fine, but it’s your responsibility to unplug the cable when temperatures warm and plug it back in when freezing temperatures return.
Material safety
Some heat cables may not be safe to use with certain materials, so you need to know the materials used in your roof, gutters, and downspouts.
Additionally, all heat cables should be waterproof. An inexpensive heat cable that doesn’t offer water protection is not safe to use.
Finally, check the rating for the cable in extremely low temperatures. If the heat cable’s insulation layer may crack in low temperatures, it is not safe for you to use.
For example, some pipe heating cables may market themselves as gutter deicing cables, too. However, pipe heat tape is made for use in crawl spaces where it’s not exposed to the full winter elements. Be careful about using this type of material to deice your gutters in locations where temperatures can be extremely low.
Watts per foot
The number of watts per foot that a heat cable generates provides information on its heating power. A cable with five to seven watts per foot is average and suits the majority of homeowners. For tougher ice situations, some deicing cables may carry 10 or more watts per foot. However, cables that have a higher watts per foot rating use more electrical power, generating higher costs.
If the manufacturer doesn’t list the product’s watts per foot rating in the specifications, you can calculate this number if you know the total length and total watts the cable carries.
Roof and gutter heat cables prices
Heat cables for roofs and gutters have widely varying price points, primarily depending on the length of the cable. To simplify comparisons, calculate the cost of each cable per foot. This allows you to fairly compare prices of an 80-foot cable with a 90-foot cable.
To further compare products, pay attention to the length of the cold lead. With a lengthy cold lead you pay a little more, but you also potentially avoid the extra cost of an extension cable.
Inexpensive: Inexpensive heat cables that have only basic features may cost $1 to $2 per foot for cables of less than 50 feet in length. For cables with lengths greater than 50 feet, you may pay $0.50 to $1.50 per foot for a basic cable.
Mid-range/Expensive: Heat cables with plenty of extra features have a higher cost per foot. For cables of less than 50 feet of length, expect to pay $2 to $4 per foot. Beyond 50 feet in length, high-end heat cables range from $1.50 to $3 per foot.
If your heat cable doesn’t ship with the clips needed to secure it to the roof, you’ll need to spend a few extra dollars for this hardware.
Caution
If the insulation sheath in the heat cable is punctured during installation, you run the risk of a fire. Inspect the cable before plugging it into an outlet.
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Tips
As snow is warmed by the rising heat inside your home and melts on portions of the roof that are directly above your living area, the melt runs down the slanted roof. However, it may run into frozen snow and ice inside the gutter or on the eave, which doesn’t receive heat transferred from the living area.
If a part of your roof is in constant shadow, it may have thicker ice than areas of the roof that get some sunlight. The thick ice blocks snowmelt from reaching the gutter.
With nowhere to go, the water refreezes and expands. The expanding ice may penetrate under your shingles or flashing. As it melts again later, it can cause damage to your home, often resulting in a leaking ceiling.
Beyond making use of a heat cable, here are a few other ways to prevent problems from ice backing up on your roof or in your gutters.
Remove leaves from the gutter. Even though no one likes doing it, clean out your gutters, removing fallen leaves before the winter season. If the gutters are clogged with leaves, the water cannot drain properly, creating large chunks of frozen ice in the gutters and further blocking snowmelt.
Keep the downspout exit area flowing freely. Once the water exits the downspout it should continue flowing away from the home. You don’t want to block the exit area — this can cause water to freeze at the immediate end of the downspout and hinder other water from exiting.
- Fix any loose shingles before winter. If you have roof damage or loose shingles, ice dams may exploit these areas. Try to fix any roof issues before the winter season begins. Check the flashing, too, as ice dams can push flashing out of the way, creating areas for water to penetrate and leak into your home.
FAQ
Q. How do I know the heat cable length I need for a gutter?
A. Measure the length of the gutter where you want to stretch the cable, then figure out how far (to the nearest foot) the eave extends beyond the exterior wall of the home. Multiply the gutter length by four if the eave is roughly one foot, by five for a two-foot eave, and by six for a three-foot eave. This should give you a rough idea of the length of cable you need.
Q. How much heat cable do I need to run the cable inside a downspout?
A. Measure the length of the downspout. If the end of the heat cable stops in the downspout, use that measurement. However, if you need to use the cable inside the downspout and then run it back along more gutter or roofline, double the cable length measured for the downspout. You have to drop the middle of the cable through the downspout, so you need twice as much.
Q. Should I leave the heat cable plugged into an outlet all winter?
A. Not necessarily. The cable has no on/off switch, so if it’s plugged into an outlet, it is drawing power. For better energy efficiency, only plug in the cable when there’s moisture in the gutters that could freeze, or purchase a cable with an automatic sensor. It can turn itself on and off automatically, so it can be plugged in continuously.
Q. Can I unplug the cable as soon as the air temperature is above freezing?
A. We don’t recommend this. If the area where the heat cable is installed is in shadow, the water or snowmelt in the area could refreeze as it moves into the shadow, even in above-freezing air temperatures. Leave the cable plugged in until you’re sure the moisture is gone or will not refreeze.
